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Thursday, October 20, 2005
Climate change reduces rice yield
LOS BAÑOS - Climate change resulting from human activity is likely to lead to reduced rice yields and the problem may only be manageable if action is taken starting right now, International Rice Research Institute (Irri) experts said last Tuesday.
Emissions of carbon dioxide, a major greenhouse gas, were likely to double over time and this would “drive yields down by 0.15 tons per hectare (2.47 acres) in 50 years,” said John Sheehy, a senior Irri scientist.
He said this would come on top of the pressure from a rapidly-growing population and increased competition for water, land and other resources needed to grow the staple food of nearly half the human race.
By 2030 alone, rice yields “must increase by 30-40 percent” to match population growth, a clip which is above the increase in production of the cereal over the past 15 years, IRRI deputy director William Padolina told a news briefing.
Over 50 years, a 62 percent rise in rice yields is required just to keep pace with population growth, said Sheehy, an expert in crop ecology.
Sheehy said warmer temperatures, which are both the products of human activity as well as the earth’s natural longer-term warming and cooling cycle, are projected to lead to warmer and wetter weather, and a rise of sea levels of about 50 centimeters (20 inches) over the next half century.
Extreme weather is also “going to become more frequent,” he said.
Increased carbon dioxide levels, which would enhance photosynthesis or starch production in plants, would be favorable to growing rice but would also raise temperatures and so would cut yields.
A one-degree Celsius rise in temperature would lead to a 0.6 ton drop in rice yield per hectare, while every 75 parts per million increase in carbon dioxide from the current level of 375 parts per million would cut rice production by half a ton per hectare, Sheehy said. (AFP)
(October 20, 2005 issue)
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